GNOME Shell: Input lag when using multimedia keys

After years of using Xfce, I'm back to GNOME. Quite impressed with how much it evolved since the last time I used it.

However, one thing that's bothering me is this weird one-second lag between keypressing and feedback, on Xorg, that only happens with the multimedia keys. There's another one-second lag if I press other key. The entire screen freezes for this one second, but I can still move the mouse. Audio isn't affected.

On Wayland, it's the mouse pointer that starts lagging behind when the Shell draws its animations. Disabling animations doesn't help that much, though. But this is a known bug with no known solution as far as I'm aware.

I'm on Fedora 26 beta, latest version of the shell (3.24.2). Hardware is an AMD A10-7860K with the IGP (Radeon R7) and the open-source drivers.